“She grabbed it and screamed for help before running back into the shop.”

Webber was arrested 12 hours later and told officers that the reason he had made the demand for money was that he had a heroin habit and he was desperate.

James Evans, defending Webber, who has 20 convictions for 46 offences – 21 of them for theft – said that Webber had made a conscious decision some years ago that he was going to change his ways and in 2004 stopped offending.

“But there was a tragedy and that made him go back to drugs,” he said.

Judge John Curran jailed Webber for two years and told him that his victim was still suffering the after-effects of the attempted robbery and was still in shock, worried about going out on her own.